The scaling of complementary metal-oxide semiconductor (CMOS) technology leads to a greater difficulty in the integration of both floating gate memory and logic together for high performance and low power memory circuits. The floating gate memory provides one programmable memory (OTP) and embedded Flash memory. Embedded Flash memory is typically 2 or 3 nodes behind leading edge CMOS technology, because of the complexity of integrating additional processing (which also increases the costs). As a result, one-time programmable (OTP) memory is being used increasingly for embedded non-volatile memory (NVM) applications.
Two types of OTP memory are currently available on CMOS technology at or below 65 nm: electrical fuse (eFuse) and anti-fuse. An eFuse memory element is programmed by forcing a high current density through a conductive link in order to completely rupture it or make its resistance significantly higher such that the link is no longer conductive (the link is high resistance or open circuit). Anti-fuse is the opposite of an eFuse. The circuit is originally open (high resistance) and is programmed by applying electrical stress that creates a low resistance conductive path.
eFuse programming, however, requires high current, it is programmed during production of the device and programming during the operation of the chip on which it resides. The use of charge trapping in metal-oxide semiconductor (MOS) transistors, and in particular using channel hot charge (CHC) injection for programming, has been developed. However, programming typically requires high power and has low programming efficiency. For example, logic high K/metal gate (HK/MG) OTP devices are programmed by MOS device operation. It may generate charge trap closing in a drain side of gate dielectric when device is programmed due to CHC injection. However, to reduce power and energy, a weak program condition may be applied. The weak program condition has less Vt shift and without gate breakdown, a small program window, and weak data retention performance.
Accordingly, there is a need for systems, apparatus, and methods that improve upon conventional approaches including the improved methods, system and apparatus provided hereby.
The inventive features that are characteristic of the teachings, together with further features and advantages, are better understood from the detailed description and the accompanying figures. Each of the figures is provided for the purpose of illustration and description only, and does not limit the present teachings.